JP4219766B2 - Image generation program and image generation apparatus - Google Patents

Description

  The present invention relates to an image generation program and an image generation apparatus, and in particular, for example, a target object that is an operation target of a player such as a player object and a non-target object that is not an operation target such as a terrain object or a building object are arranged. Image generation program and image generation for generating an image visible from a virtual camera by projecting and transforming a state of a three-dimensional virtual space onto a projection plane based on a virtual camera arranged in the virtual space and drawing in a drawing area Relates to the device.

An example of this type of conventional image generation apparatus is disclosed in Patent Document 1. In the sports game apparatus disclosed in Patent Document 1, when an image of a field viewed from a viewpoint placed directly above the field is generated, the side line on the upper side is previously thicker than usual. This field is perspective-transformed to obtain an image in which the field is looked down from the side. In this way, the side line displayed on the back side of the screen was properly displayed without fading or interruption.
JP 2001-149649 A [A63F 13/00, 13/10, 13/12, G06T 17/00]

  As described above, in order to effectively show the three-dimensional model, the camera normally uses an angle from an oblique direction, and actually displays a rectangular field distorted in a trapezoidal shape. In a 3D game program or 3D game device for realizing a game (3D game) in a three-dimensional game space, the tilt direction of the stick provided in the controller corresponds to the moving direction of the object in the 3D virtual space. For example, it is common that a player object in a 3D virtual space is programmed to move in a 45-degree direction (oblique direction) by tilting the stick forward by 45 degrees. In such a 3D game program and the like, an image viewed from a virtual camera in a 3D virtual space is perspective-transformed by a perspective projection method and displayed on a television screen, so that the depth direction is reflected even though it is a two-dimensional image. Is done. For this reason, in the 3D game, when the stick is operated as it is seen on the television screen, there is a problem that the object cannot be moved as the player desires. For this reason, for example, in order to move an object (player object) along the line of a field that is originally a rectangle, a certain amount of space grasping ability (seeing a screen displayed in two dimensions, the state is expressed in three dimensions Therefore, the operation was not easy for everyone.

  Specifically, there is a rectangular parallelepiped character object (player object) in front of a cubic terrain object placed in the 3D space, and this is taken by a virtual camera from an oblique (45 degrees) direction. The game image as shown in FIG. 15 is displayed on the display (television screen). As can be seen from FIG. 15, even in the 3D space, even if the side surface (wall) of the terrain object extends in the direction of 45 degrees, the angle on the television screen is different, and in the wall facing the character object, 45 degrees. The angle is smaller than that. For example, when the angle of the virtual camera (the angle formed by the straight line connecting the virtual camera and the gazing point and the horizontal plane of the 3D space) is 45 degrees, the angle of the wall of the terrain object facing the character object is 22 degrees. It will be displayed in the degree. Since the player operates the movement of the character object while watching such a television screen, for example, when the character object is moved along the wall, the direction of 22 degrees is instructed by the stick. As a result, the character object moves in the game space in the direction of 22 degrees, but intends to move along the wall extending in the direction of 45 degrees, so that it moves at a narrower angle (for example, 10 degrees) on the television screen. Has been displayed.

  SUMMARY OF THE INVENTION Therefore, a main object of the present invention is to provide an image generation program and an image generation apparatus that can realize a simple operation of an object.

  Another object of the present invention is to provide an image generation program and an image generation apparatus capable of grasping a space as if looking down from directly above, even in a three-dimensional space captured from an oblique angle.

  In order to solve the above problems, the present invention employs the following configuration. Note that reference numerals and figure numbers in parentheses indicate correspondence with embodiments described later to help understanding of the present invention, and do not limit the scope of the present invention.

  Claim 1 includes a target object (82) that is an operation target of the operation means (22; reference numeral shown in the embodiment; the same applies hereinafter) and a plurality of non-target objects (84) other than the operation target. The state of the three-dimensional virtual space is projected and converted to a projection plane (88) based on the virtual camera (86) in the virtual space (80; world coordinate system), and drawn in the drawing area (48) so that it can be seen from the virtual camera. An image generation program that causes a computer (36, 42) to execute processing for generating an image, and causes the computer to operate yesterday as a magnification calculation unit and a projection drawing unit. The magnification calculation means (S23) moves the computer in either one of a first direction (horizontal direction of the projection plane) on the projection plane of the virtual camera or a second direction (vertical direction of the projection plane) perpendicular to the first direction. On the other hand, the magnification for enlarging or reducing the non-target object projected on the projection plane is based on the angle at which the virtual camera is oriented with respect to the horizontal plane in the virtual space (XZ plane in the world coordinate system). Make it work to calculate. The projection drawing means (S11) performs parallel projection conversion (S51) of the non-target object to the projection plane and enlarges or reduces the non-target object projected on the projection plane based on the magnification. Function to draw in the drawing area.

  According to the first aspect of the present invention, the non-target object is enlarged or reduced by the magnification calculated based on the angle of the virtual camera facing the horizontal plane of the virtual space and drawn in the drawing area. For example, it is possible to display only the target object on a television screen, for example, as viewed from directly above.

  A second aspect is dependent on the first aspect, wherein the magnification calculating means makes the horizontal cross-sectional shape of the non-target object projected on the projection plane substantially the same as the horizontal cross-sectional shape of the non-target object before the projection conversion in the virtual space. As described above, the computer is caused to function so as to calculate the magnification for enlarging or reducing in the first direction or the second direction on the projection plane based on the angle at which the virtual camera is facing.

  According to the invention of claim 2, the non-target object can be displayed in a shape as seen from directly above in the virtual space. In other words, even in a three-dimensional space captured from an oblique angle, the space can be grasped as if viewed from directly above.

  A third aspect is dependent on the first or second aspect, wherein the projection / drawing means causes the enlargement / reduction process to be executed on all the objects in the clipping region in the virtual space, and the enlargement / reduction process is executed. The computer further functions as an arrangement unit that arranges the horizontal cross-sectional shape of the target object in a reduced or enlarged manner so that the shape of the target object returns to the original shape.

  According to the invention of claim 3, for example, when the projection drawing means (S9, S11) executes the enlargement process, the horizontal sectional shape of the target object is reduced, and conversely the projection drawing means performs the reduction process. When executing, the horizontal cross-sectional shape of the target object is enlarged. Therefore, since the target object is displayed as it is, there is no inconvenience that the reality of the game is unnecessarily impaired, and the interest in the game is not diminished.

  A fourth aspect of the present invention is dependent on any one of the first to third aspects, wherein the projection drawing means generates a determinant for performing parallel projection conversion and enlarging or reducing based on the magnification, and performing the projection conversion and the conversion based on the determinant. After enlarging or reducing the image, the computer is caused to function so as to draw the object in the drawing area.

  According to the fourth aspect of the present invention, the projection conversion and the enlargement / reduction process are executed according to the determinant, so that the coordinate conversion can be easily performed.

  A fifth aspect is dependent on any one of the first to fourth aspects, and further causes the computer to function as camera angle detection means for detecting an angle at which the virtual camera faces the horizontal plane of the virtual space.

  According to the invention of claim 5, since the object projected on the projection plane is reduced at the magnification based on the detected angle, for example, if the object is enlarged by the inverse of the magnification, the shape of the target object is changed to the original shape. Can be returned to.

  A sixth aspect is dependent on any one of the first to fifth aspects, wherein the enlargement direction is a vertical direction relative to the projection plane, and the reduction direction is a horizontal direction relative to the projection plane.

  According to the sixth aspect of the present invention, the non-target object viewed obliquely from above with the virtual camera can be displayed as viewed from directly above.

  A seventh aspect is dependent on any one of the first to sixth aspects, and the non-target object includes a terrain object or a building object.

  According to the invention of claim 7, the shape is changed by a background object such as a terrain object or a building object, and a character object such as a player object is displayed as it is. Reality is not impaired more than necessary. That is, it is possible to prevent a decrease in interest in the game.

  According to another aspect of the present invention, a state of a three-dimensional virtual space in which a target object that is an operation target of the operation means and a plurality of non-target objects other than the operation target are arranged is projected and converted to a projection plane based on a virtual camera in the virtual space. And an image generation device that generates an image that can be seen from a virtual camera by drawing in a drawing area. The image generation apparatus enlarges or reduces the non-target object projected on the projection plane with respect to either the first direction on the projection plane of the virtual camera or the second direction orthogonal to the first direction. A magnification calculating means for calculating a magnification for the image based on an angle at which the virtual camera is facing the horizontal plane in the virtual space, and a non-target object that is parallel projected on the projection plane and projected onto the projection plane Projection drawing means for drawing a non-target object in a drawing area by enlarging or reducing the target object based on a magnification.

  In the invention of claim 8, as in the invention of claim 1, the non-target object is enlarged or reduced by the magnification calculated based on the angle of the virtual camera facing the horizontal plane of the virtual space to the drawing area. Since the drawing is performed, only the non-target object can be displayed on the television screen as if viewed from directly above.

  A ninth aspect is dependent on the eighth aspect, wherein the magnification calculating means makes the horizontal cross-sectional shape of the non-target object projected onto the projection plane substantially the same as the horizontal cross-sectional shape of the non-target object before the projection conversion in the virtual space. Thus, the magnification for enlarging or reducing in the first direction or the second direction on the projection plane is calculated based on the angle at which the virtual camera is facing.

  A tenth aspect is dependent on the eighth or ninth aspect, wherein the projection / drawing means executes enlargement / reduction processing for all objects in the clipping region in the virtual space, and the enlargement / reduction processing is performed by the projection / drawing means. Arrangement means is further provided for reducing or enlarging the horizontal cross-sectional shape of the target object so that the shape of the target object returns to the original shape when executed.

  An eleventh aspect is dependent on any one of the eighth to tenth aspects, wherein the projection drawing means generates a determinant for performing parallel projection conversion and enlarging or reducing based on magnification, and performing projection conversion and After executing the enlargement or reduction process, the object is drawn in the drawing area.

  A twelfth aspect is dependent on any one of the eighth to eleventh aspects, and further includes camera angle detection means for detecting an angle of the virtual camera facing the horizontal plane of the virtual space.

  A thirteenth aspect is dependent on any one of the eighth to twelfth aspects, wherein the enlargement direction is a vertical direction with respect to the projection plane, and the reduction direction is a horizontal direction with respect to the projection plane.

  A fourteenth aspect is dependent on any one of the eighth to thirteenth aspects, and the non-target object includes a terrain object or a building object.

  According to the present invention, a non-target object such as a building object or a wall object projected on the projection plane is enlarged or reduced at a magnification based on the angle of the virtual camera, so that the non-target object on the screen is viewed from directly above. Is displayed. Thereby, for example, when moving the target object along the non-target object displayed on the TV screen or the like, the movement direction of the target object by the operation of the operation means matches the movement direction of the target object on the TV screen. The target object can be easily operated. That is, operability can be improved.

  The above object, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

  With reference to FIG. 1, a video game system 10 including a video game apparatus 12 including an image generation program or an image generation apparatus according to an embodiment of the present invention will be described. The video game apparatus 12 is supplied with power, but in the embodiment, this power may be a general AC adapter (not shown). The AC adapter is plugged into a standard household wall socket and converts the household power supply to a low DC voltage suitable for driving the video game device 12. As another example, a battery may be used as a power source.

  The video game apparatus 12 includes a substantially cubic housing 14, and an optical disk drive 16 is provided on the upper end of the housing 14. An optical disk 18 which is an example of an information storage medium storing a game program or the like is mounted on the optical disk drive 16. A plurality of (four in the embodiment) connectors 20 are provided on the front surface of the housing 14. These connectors 20 are for connecting the controller 22 to the video game apparatus 12 by the cable 24. In this embodiment, a maximum of four controllers 22 can be connected to the video game apparatus 12.

  The controller 22 is provided with an operation unit (operation switch) 26 on its upper surface, lower surface, or side surface. The operation unit 26 includes, for example, two analog joysticks, one cross key, a plurality of button switches, and the like. One analog joystick is used to input the moving direction and / or moving speed or moving amount of a player object (moving image object that can be operated by the player by the controller 22) according to the tilt amount and direction of the stick. Other analog joysticks control the movement of the virtual camera according to the tilt direction. The cross switch is used to instruct the moving direction of the player object instead of the analog joystick. The button switch is used to instruct the movement of the player object, is used to switch the viewpoint of the virtual camera of the three-dimensional image, and is used to adjust the movement speed of the player object. The button switch further controls, for example, menu selection and pointer or cursor movement.

  In this embodiment, the controller 22 is connected to the video game apparatus 12 by a cable 24 provided integrally therewith. However, the controller 22 may be connected to the video game apparatus 12 by other methods, for example, wirelessly via electromagnetic waves (for example, radio waves or infrared rays). The specific configuration of the operation unit 26 of the controller 22 is not limited to the configuration of the embodiment, and can be arbitrarily modified. For example, only one analog joystick may be used or not used. The cross switch may not be used.

  One or more (two in this embodiment) memory slots 28 are provided on the front surface of the housing 14 of the video game apparatus 12 and below the connector 20. A memory card 30 is inserted into the memory slot 28. The memory card 30 loads and temporarily stores a game program or the like read from the optical disc 18, or saves (saves) game data (for example, game results) of a game played using the game system 10. It is used for storing.

  An AV cable connector (not shown) is provided on the rear surface of the housing 14 of the video game apparatus 12, and the monitor 34 is connected to the video game apparatus 12 through the AV cable 32 using the connector. The monitor 34 is typically a color television receiver, and the AV cable 32 inputs a video signal from the video game apparatus 12 to a video input terminal of the color television and inputs an audio signal to the audio input terminal. Therefore, for example, a game image of a three-dimensional (3D) video game is displayed on the screen of the color television (monitor) 34, and stereo game sounds such as game music and sound effects from the left and right speakers 34a, or two speakers. When a surround effect can be produced, game sound including surround sound is output.

  In this game system 10, in order for a user or game player to play a game (or other application), the user first turns on the video game device 12, and then the user wants to play the video game (or other that he / she wants to play). The appropriate optical disk 18 storing the application) is selected, and the optical disk 18 is loaded into the disk drive 16 of the video game apparatus 12. In response, the video game device 12 starts to execute a video game or other application based on the software stored on the optical disc 18. The user operates the controller 22 to provide input to the video game device 12. For example, a game or other application is started by operating one of the operation units 26. By moving other parts of the operation unit 26, the moving image object (player object) can be moved in different directions, or the user's viewpoint (camera position) in the three-dimensional (3D) game world can be changed.

  FIG. 2 is a block diagram showing an electrical configuration of the video game system 10 of FIG. 1 embodiment. The video game apparatus 12 is provided with a central processing unit (hereinafter referred to as “CPU”) 36. The CPU 36 is also called a computer or a processor, and is responsible for overall control of the video game apparatus 12. The CPU 36 or the computer functions as a game processor, and a memory controller 38 is coupled to the CPU 36 via a bus. The memory controller 38 mainly controls writing and reading of the main memory 40 coupled via the bus under the control of the CPU 36. A GPU (Graphics Processing Unit) 42 is coupled to the memory controller 38.

  The GPU 42 forms part of the drawing means, and is constituted by, for example, a single chip ASIC. The GPU 42 receives a graphics command (graphics command) from the CPU 36 via the memory controller 38, and the geometry unit 44 and the rendering according to the command. A unit 46 generates a three-dimensional (3D) game image. That is, the geometry unit 44 is a rotation of various objects and objects (consisting of a plurality of polygons. The polygon is a polygonal plane defined by at least three vertex coordinates), Coordinate calculation processing such as movement and deformation is performed. The rendering unit 46 performs image generation processing such as pasting a texture (texture: pattern image) to each polygon of various objects. Therefore, 3D image data to be displayed on the game screen is created by the GPU 42, and the image data is stored in the frame buffer 48.

  Note that data (primitives, polygons, textures, etc.) necessary for the GPU 42 to execute the drawing command is acquired from the main memory 40 by the GPU 42 via the memory controller 38.

  The frame buffer 48 is a memory for drawing (accumulating) image data for one frame of the raster scan monitor 34, for example, and is rewritten frame by frame by the GPU. Specifically, the frame buffer 48 stores image color information in order for each pixel (pixel). Here, the color information is data about R, G, B, and A. For example, 8-bit R (red) data, 8-bit G (green) data, 8-bit B (blue) data, and 8 Bit A (alpha) data. The A data is data about the mask (mat image). A video I / F 58 described later reads data from the frame buffer 48 via the memory controller 38, whereby a 3D game image is displayed on the screen of the monitor 34.

  The Z buffer 50 has a storage capacity corresponding to the number of pixels corresponding to the frame buffer 48 × the number of bits of depth data per pixel, and the depth information or depth of the dots corresponding to each storage position of the frame buffer 48. Data (Z value) is stored.

  Note that both the frame buffer 48 and the Z buffer 50 may be configured using part of the main memory 40.

  The memory controller 38 is also coupled to the ARAM 54 via a DSP (Digital Signal Processor) 52. Therefore, the memory controller 38 controls writing and / or reading of not only the main memory 40 but also the ARAM 54 as a sub memory.

  The DSP 52 functions as a sound processor and is necessary for the game by using sound data 404b (see FIG. 3) stored in the main memory 40 or using sound waveform data (not shown) written in the ARAM 54. Audio data corresponding to a sound, voice or music is generated.

  Memory controller 38 is further coupled to each interface (I / F) 56, 58, 60, 62 and 64 by a bus. The controller I / F 56 is an interface for the controller 22 and supplies an operation signal or data of the operation unit 26 of the controller 22 to the CPU 36 through the memory controller 38. The video I / F 58 accesses the frame buffer 48, reads the image data created by the GPU 42, and supplies the image signal or image data (digital RGBA pixel value) to the monitor 34 via the AV cable 32 (FIG. 1).

  The external memory I / F 60 links the memory card 30 (FIG. 1) inserted in the front surface of the video game apparatus 12 to the memory controller 38. Thereby, the CPU 36 can write data to the memory card 30 or read data from the memory card 30 via the memory controller 38. The audio I / F 62 receives the audio data supplied from the DSP 52 or the audio stream read from the optical disc 18 through the memory controller 38 and supplies an audio signal (audio signal) corresponding to the audio data to the speaker 34 a of the monitor 34.

  In the case of stereo sound, at least one speaker 34a is provided on each of the left and right speakers. In addition, by performing the surround processing, it is possible to let the sound be heard as if the sound is generated from the rear even with only the two left and right speakers.

  The disk I / F 64 couples the disk drive 16 to the memory controller 38, so that the CPU 36 controls the disk drive 16. Program data, texture data, and the like read from the optical disk 18 by the disk drive 16 are written into the main memory 40 under the control of the CPU 36.

  FIG. 3 shows a memory map of the main memory 40. The main memory 40 includes a program storage area 402 and a data storage area 404. Programs such as a game main processing program 402a, an image generation program 402b, and an image display program 402c are stored in the program storage area 402.

  The game main processing program 402 a is a program that processes a main routine for a game executed by the video game apparatus 12. The image generation program 402b includes a moving image object such as a player object and an enemy (opposition opponent) object appearing in the game, an item object (item object) used by the moving image object, and a background object (terrain object) of the game. , A wall object, a building object, a floor object, and the like). Hereinafter, in this embodiment, the above-mentioned moving image object and item object may be collectively referred to as a “character object”. The image display program 402c is a program for displaying the game image generated by the image generation program 402b on the monitor 34.

  The data storage area 404 stores data such as image data 404a, sound data 404b, and determinant data 404c. The image data 404a is data such as polygon data and texture data for generating a game image as described above. Specifically, the image data of the character object appearing in the game and the image data of the background object. The sound data 404b is data on music (BGM) played during the game and sound (music) such as sound effects. The determinant data 404c is data about determinants (model matrix, camera matrix, and projection matrix) generated in the image generation process, as will be described later.

  Although not shown, the main memory 40 also stores game data, flag data, and the like generated as the game progresses.

  For example, as shown in FIG. 4A, in the 3D virtual space 80, there is a character object 82 such as a player object whose arbitrary action such as movement is controlled according to the operation of the controller 22 (control means 26). Be placed. Further, a background object 84 such as a terrain object, a wall object, a building object, and a floor object is arranged at a predetermined position in the virtual space 80 without the operation of the controller 22. A virtual camera 86 is further arranged at a predetermined position in the virtual space 80, and an image (game image) taken by the virtual camera 86 is displayed on the monitor 34.

  In such a 3D virtual game, the 3D virtual space 80 is displayed on the monitor 34 as a two-dimensional image. For this reason, it is necessary to project and display a three-dimensional object on a two-dimensional plane (screen). Also, when looking at an object placed in a three-dimensional space, an object closer to the viewpoint looks larger and a far object looks smaller, so when projecting onto a screen, it is generally perspective projected. . Thereby, the parsed game image is displayed on the monitor 34. For example, a game image taken by the virtual camera 86 in FIG. 4A is displayed on the monitor 34 as shown in FIG. 4B. As can be seen from FIG. 4B, the square plate-like background object 84 arranged in the virtual space 80 is transformed into a trapezoidal shape when displayed on the screen.

  The player operates the controller 22 while viewing the game image. Usually, the tilt direction of the joystick provided in the controller 22 corresponds to the direction of the 3D virtual space 80 (world coordinate system). When moving 82 along the side of the background object 84 toward the back of the screen, the joystick may be tilted directly upward.

  However, since the background object 84 is displayed in a trapezoidal shape in the game image, the player tilts the joystick diagonally upward to move the character object 82 along the oblique side of the trapezoidal background object 84. Sometimes. Then, the character object 82 moves toward the inside of the background object 84, and the operation direction of the player (inclination direction of the joystick) does not match the movement direction of the character object 82 on the screen. Thus, in the 3D virtual game, moving the character object 82 requires a certain amount of space grasping ability (the state can be grasped as a three-dimensional space by looking at the screen displayed two-dimensionally).

  Therefore, in this embodiment, a game image that can easily move the character object 82 is displayed on the monitor 34 without requiring space grasping ability. The contents will be described below.

  First, the concept of the game image generation method in this embodiment will be described with reference to FIGS. As shown in FIG. 5, in this embodiment, a game image taken by the virtual camera 86, that is, a game image viewed from the virtual camera 86 is parallel projected onto a two-dimensional plane (screen) 88 (also called orthogonal projection or orthographic projection). .) However, FIG. 5 shows a state where the virtual space 80 shown in FIG. 4A is rearranged in the visual field space, and the character object 82 is omitted for simplicity. At this time, the length X ′ of the object (projected object) 84 ′ projected on the screen 88 is made shorter than the length X of the original background object 84. In the example illustrated in FIG. 5, the length X ′ of the projection object 84 ′ is cos (90−θ) times the length X of the background object 84. Is the angle of the virtual camera 86 (hereinafter referred to as “camera angle”).

  That is, as shown in FIG. 6A, the screen 88 displays an image of the background object 84 that has been transformed into a rectangle (squeezed in the vertical direction). Here, even when the parallel projected game image is displayed on the television monitor 34 as it is, the operation direction of the controller 22 and the movement direction of the character object 82 on the screen coincide. However, since the vertical length of the background object 84 is shortened during parallel projection, when the player moves the character object 82 around the background object 84 by operating the controller 22, A difference occurs between the speed at which the character object 82 moves along the vertical side and the speed at which the character object 82 moves along the horizontal side, and the player feels uncomfortable. This is because the background object 84 arranged in the 3D virtual space 80 is a square, and all the sides have the same length.

  Therefore, in this embodiment, not only parallel projection but also the shape of the background object 84 projected on the screen 88 is deformed to avoid such a sense of incongruity. That is, the background object 84 multiplied by cos (90−θ) is returned to the same or substantially the same size (shape) as the original. Specifically, as shown in FIG. 6A, from the length H of the screen 88, the portion corresponding to the length cos (90-θ) H is extracted with reference to the center of the screen 88, and the extracted portion. Is enlarged so as to have a length H, and is drawn in the drawing buffer (frame buffer 48). Then, the background object 84 has the same or substantially the same size as the size in the 3D virtual space 80 as shown in FIG. 7, and is displayed on the monitor 34 as viewed from directly above.

  In this way, by specifying (extracting) a range smaller than normal as a drawing area, if it is made to correspond to the frame buffer 48 of the same range with the same viewport setting as usual, the result seems to be enlarged. is there.

  However, for a character object 82 (object to be operated) whose action such as movement is controlled by the controller 22 like a player object, changing the shape of the character object 82 may damage the reality of the game. As shown in FIG. 6B, only the position of the background object 84 is moved without changing the shape.

  The character object 82 such as an enemy object is not an operation target of the controller 22 because an arbitrary action such as movement is controlled in accordance with the game program. However, even if these are transformed and displayed, the reality of the game Are excluded from non-operational targets because there is a risk of reducing interest in the game itself. That is, the shape of the character object 82 such as an enemy object is not changed as in the player object.

  Specifically, in rendering, local coordinate data for model data of a 3D model (such as a character object and a background object) is placed in the virtual space 80 according to the model matrix, and then rearranged in the view space according to the camera matrix, and The projection matrix is projected in two dimensions, and finally, the two-dimensional coordinate system is converted into the coordinate system (address) of the frame buffer 48 by the viewport setting, and the color is painted.

  In this embodiment, among the above processes, when generating a model matrix, a camera matrix, and a projection matrix, enlargement scaling (scale multiplication) as described above is performed by adopting a calculation method different from the normal method. Like that. Hereinafter, it demonstrates concretely, referring drawings.

  As shown in FIG. 8 (A), the camera angle is set so that a cube-shaped background object 84 is arranged in a three-dimensional virtual space 80 in the same manner as a cube-shaped character object 82 in a normal model matrix, and these are photographed. A virtual camera 86 with θ set at 45 degrees is arranged. However, for the sake of simplicity, the length of each side of the character object 82 and the background object 84 is “1”.

  Next, when the virtual space 80 shown in FIG. 8A is subjected to calculation processing according to a normal camera matrix, the virtual space 80 is arranged in a visual field space centered on the virtual camera 86 as shown in FIG. 8B. Will be fixed. Then, the visual field space is projected in parallel on a two-dimensional plane (screen 88) according to a normal projection matrix. At this time, in FIG. 8A, the upper surfaces (surfaces (sides) horizontal to the ground of the virtual space 80) and side surfaces (surfaces perpendicular to the ground of the virtual space 80) ( Side)) is cos θ times (here, θ = 45 °, so 1 / √2 times). However, for simplicity, √2≈1.4 and 1 / √2≈0.7. The same applies hereinafter.

  Here, as described above, if only enlargement scaling is performed, not only the upper surface but also the side surface is enlarged. In such a case, the entire screen is only displayed in the vertical direction of the television monitor 34, and is almost the same as a screen on which normal parallel projection is performed. Therefore, in order to perform enlargement scaling only on the upper surface, a camera matrix is generated so that the objects (the character object 82 and the background object 84) appear to be crushed in the vertical direction (1 / scale times). As a result, the character object 82 and the background object 84 displayed on the screen appear to be enlarged and scaled only on the upper surface (horizontal direction) and are not enlarged and scaled on the side surface (vertical direction).

  However, for the character object 82, in order to completely eliminate the distortion of the shape, a model matrix that cancels the expansion scaling in the horizontal direction that cannot be compensated only by the cancellation by the camera matrix is generated. That is, a model matrix is generated that appears to be collapsed (1 / scale times) only in the horizontal direction.

  Specifically, as the model matrix, a model matrix (Equation 1) for the background object 84 and a model matrix (Equation 2) for the character object 82 are generated. The coordinates on the virtual space 80 where the origin position of the local space (the space in the virtual space 80 that can be photographed by the virtual camera 86) is to be taken are (Px, Py, Pz) and the X axis of the local space is pointed The unit vector on the desired virtual space 80 is (Xx, Xy, Xz), the unit vector on the virtual space 80 where the local space Y axis is to be directed is (Yx, Yy, Yz), and the local space Z axis is When a unit vector on the virtual space 80 to be directed is (Zx, Zy, Zz), a normal model matrix is expressed by Equation 1. The model matrix represented by Equation 1 is a model matrix for arranging the background object 84 in the virtual space 80.

  As described above, the character object 82 has a direction (nx, 0, nz) (; length) which is parallel to the horizontal plane and becomes the vertical direction of the screen of the television monitor 34 in order to eliminate distortion of the shape. A model matrix as shown in Equation 2 is generated so that the shape is collapsed to (unit vector of 1) and arranged (1 / scale times). The model matrix shown in Equation 2 is generated based on the model matrix shown in Equation 1.

  When the character object 82 and the background object 84 are arranged in the three-dimensional virtual space 80 in accordance with such a model matrix, as shown in FIG. 9A, the character object 82 is displayed as being crushed only in the horizontal direction. Is done. Here, the rate at which the character object 82 is displayed as if collapsed only in the horizontal direction is determined by the camera angle θ of the virtual camera 86. As described above, since the camera angle θ is set to 45 degrees, the character object 82 is multiplied by 1 / √2 in the horizontal direction.

  Next, the virtual space 80 is rearranged in the visual field space with the virtual camera 86 as the center, as shown in FIG. The coordinates on the virtual space 80 where the virtual camera 86 is arranged are (Px, Py, Pz), the unit vector on the virtual space 80 facing the virtual camera 86 from the gazing point is (Zx, Zy, Zz), and the virtual The unit vector on the virtual space 80 in which the upper direction of the camera 86 is directed is defined as (Yx, Yy, Yz), and the unit vector on the virtual space 80 in the right direction of the virtual camera 86 when viewed from behind the virtual camera 86 is ( Xx, Xy, Xz), an ordinary camera matrix is expressed by Equation 3.

  However, as described above, in this embodiment, the character object 82 and the background object 84 arranged in the virtual space 80 are multiplied by 1 / scale in the vertical direction (0, 1, 0) and rearranged in the visual field space. Therefore, it is converted into a camera matrix as shown in Equation 4.

  When rearranged in the visual field space according to such a camera matrix, the side surfaces (vertical surfaces) of the character object 82 and the background object 84 are multiplied by 1 / √2 as shown in FIG. The length is set to “0.7”.

  Then, as shown in FIG. 10A, the visual field space is projected in parallel on the screen 88, and further enlarged scaling is performed. Here, the left end of the visual field projected onto the screen 88 is “left”, the right end is “right”, the upper end is “top”, the lower end is “bottom”, the front end is “near”, and the far end is “far”. Then, a normal projection matrix is expressed by Equation 5.

  However, in this embodiment, since the vertical width of the visual field space is specified to be 1 / scale times, the projection matrix of Expression 5 is converted as shown in Expression 6.

  By performing parallel projection according to Equation 6, enlargement scaling processing is executed simultaneously with the parallel projection processing.

  The projection matrix may be different from that shown in Equation 6 due to the difference in the hardware coordinate system. For example, in a three-dimensional graphics library such as OpenGL, the elements in the third row of Equation 6 are 0, 0, -2 / (far-near), and-(far + near) / (far-near), respectively.

  Therefore, as shown in FIG. 10A, when parallel projection is performed, all objects have their top and side surfaces multiplied by 1 / √2 and then subjected to enlargement scaling. √ Doubled. Therefore, for the character object 82, the side length for the upper surface and the side surface is set to about “0.5” by parallel projection, and then the length of each side is set to about “0.7” by enlargement scaling. To be. On the other hand, for the background object 84, the side length for the upper surface is set to about “0.7” and the side length for the side surface is set to about “0.5” by parallel projection. Thereafter, the length of the side with respect to the upper surface of the background object 84 is set to about “1” and the length of the side with respect to the side surface is set to about “0.7” by enlargement scaling.

  Thus, since parallel projection and enlargement scaling are performed, a game image in which only the upper surface of the background object 84 is enlarged is generated. Therefore, for example, if modeling, parallel projection, and enlargement scaling according to this embodiment are performed on the three-dimensional virtual game space that is the basis of the game image shown in FIG. A game image as shown in B) is displayed on the television monitor 34. As can be seen from FIG. 10B, the topographic object as the background object 84 is displayed as seen from directly above the top surface. For this reason, since the inclination direction of the background object displayed in the game image and the operation direction of the controller 22 match or substantially match, for example, even if the character object 82 is moved along its periphery, the operation is performed. easy.

  Further, in the example shown in FIGS. 8 to 10, since the background object 84 has a cubic shape, only the upper surface thereof is enlarged. However, in the background object 84 such as a clay pipe, the image (in the visual field space) viewed from the virtual camera 86 is shown as in FIG. 11A, and not only the top surface (end face) of the clay pipe but also a part of the inner surface. I can see it. Therefore, as described above, when this visual field space is projected in parallel and enlarged scaling is performed, an image as shown in FIG. 11B is generated. That is, the upper surface and a part of the inner surface of the clay pipe are enlarged in the vertical direction to form a circular shape. That is, enlargement scaling is performed so that the horizontal cross-sectional shape (horizontal cross-sectional shape) of the background object 84 after projection matches the horizontal cross-sectional shape of the background object 84 arranged in the three-dimensional space before projection. It can be said. Therefore, the background object 84 can be displayed as seen from directly above.

  FIG. 12 is a flowchart showing the game process of the CPU 36 shown in FIG. Referring to FIG. 12, when CPU 36 starts the game process, background object 84 for forming a ground, a building, and the like is read out and placed in a three-dimensional world coordinate system which is virtual space 80 in step S1. Next, in step S3, the character object 82 to be operated by the controller 22, that is, the player object and the virtual camera 86 are read out and similarly arranged in the world coordinate system.

  A game image generation process (image generation process) is executed in accordance with subsequent steps S5 to S11. First, in step S5, it is determined whether or not there is a movement instruction for the character object 82. That is, the CPU 36 determines whether or not an operation signal (tilt direction, tilt amount) from the joystick is held in a control buffer (not shown) provided in the controller I / F 56. If “NO” in the step S5, that is, if there is no movement instruction to the character object 82, the process directly proceeds to a step S9. On the other hand, if “YES” in the step S5, that is, if there is a movement instruction to the character object 82, the position coordinates of the character object 82 and the virtual camera 86 are calculated in accordance with an input from the controller 22 in a step S7. That is, in step S7, the post-movement position of the character object 82 is calculated according to the tilt direction and tilt amount of the joystick held in the control buffer. Further, the position of the virtual camera 86 is calculated based on the position of the character object 82 after the movement so as to face a gazing point provided at or near the foot of the character object 82.

  In step S9, a matrix generation process (see FIG. 13) described later is executed. In step S11, a geometry rendering process (see FIG. 14) described later is executed. In step S13, a game image is displayed. In step S15, it is determined whether or not the game is over. If “NO” in the step S15, that is, if the game is not ended, the process returns to the step S5 to continue the game processing. On the other hand, if “YES” in the step S15, that is, if the game is ended, the game processing is ended as it is.

  Although not shown in FIG. 12, in the game process, not only the game image display process but also the game main process, the movement of enemy objects, etc. are controlled, and the game process occurs as the game progresses. Processing such as updating game data to be performed is also executed. Further, game data generated as the game progresses is stored (saved) in the memory card 30 in accordance with a predetermined event or a player instruction.

  As shown in FIG. 13, when the CPU 36 starts the matrix generation process, the camera angle θ of the virtual camera 86 is read (detected) in step S21. The default value of the camera angle θ is 45 degrees. However, since the player can change the camera angle θ by the controller 22, it is detected in this step S21.

  In the subsequent step S23, based on the camera angle θ of the virtual camera 86, a scaling magnification (scale) such that the horizontal cross-sectional shape after projection becomes substantially the same as the horizontal cross-sectional shape (shape seen from directly above) of the object before projection. = 1 / cos (90-θ)). Next, in step S25, the scale is parallel to the horizontal plane of the world coordinate system and in the depth direction, in other words, the vertical direction of the screen of the TV monitor 34, and scaled in a direction parallel to the horizontal plane of the world coordinate system. A projection transformation matrix by parallel projection, that is, a projection matrix shown in Equation 6 is generated. Subsequently, in step S27, a camera matrix in which all the objects arranged in the world coordinate system appear to be multiplied by 1 / scale in the vertical direction, that is, a camera matrix shown in Expression 4 is generated.

  In step S29, it is determined whether or not the target object is the character object 82. If “YES” in the step S29, that is, if the target object is the character object 82, in a step S31, in a direction corresponding to the vertical direction of the TV monitor 34 screen (only in a direction parallel to the horizontal plane in the virtual space), A model matrix for multiplying only the shape by 1 / scale, that is, the model matrix shown in Formula 2, is generated, and the process proceeds to step S35. On the other hand, if “NO” in the step S29, that is, if the target object is the background object 84, a model matrix for arranging the position and the shape as they are, that is, the model matrix shown in the equation 1, is generated in a step S33. Then, the process proceeds to step S35.

  Although not shown, the model matrix data generated in steps S31 and S33, the camera matrix data generated in step S25, and the projection matrix data generated in step S23 are all data storage areas 404. Is temporarily stored.

  In step S35, it is determined whether model matrices have been generated for all objects. If “NO” in the step S35, that is, if there is an object for which a model matrix is not generated, the process returns to the step S29 as it is. On the other hand, if “YES” in the step S35, that is, if a model matrix is generated for all the objects, the matrix generating process is performed in step S37 by supplying the coordinate data of the polygons constituting the matrix and the objects to the GPU 42. To return.

  As shown in FIG. 14, when the GPU 42 starts the geometry rendering process under the instruction of the CPU 36, the shape of the character object 82 is reduced in step S41. That is, the shape of the character object (character object 82) is reduced according to the model matrix shown in Equation 2. That is, it is multiplied by 1 / scale. In a succeeding step S43, the arrangement position of the character object 82 is updated. That is, the character object 82 is moved to the position of the character object 82 after the movement calculated in step S7. However, a character object whose movement is controlled according to a game program such as an enemy object is moved to a position calculated according to the game program.

  In this embodiment, the steps S41 and S43 are described in order to facilitate understanding. However, depending on actual hardware, the steps are executed simultaneously by a single determinant.

  In the next step S45, all objects are converted into a virtual camera coordinate system. That is, the three-dimensional virtual space 80 is converted into the visual field space according to the camera matrix as shown in Equation 4. In step S47, clipping and hidden surface processing are performed. Although detailed description is omitted, in clipping, a portion protruding from a range that can be photographed by the virtual camera 86 is cut off. In the hidden surface processing, the line segments and surfaces that are not visible from the virtual camera 86 are erased.

  In the subsequent step S49, light source processing such as arranging the light source at a predetermined position and setting the light intensity of the light source is executed. Next, in step S51, parallel matrix generation processing for the projection plane (screen 88) is executed, and in step S53, a drawing area on the projection plane is designated. That is, as shown in FIG. 6A, a drawing range corresponding to the scale magnification is designated. However, as described above, in this embodiment, since the projection matrix is modified, the GPU 42 executes the processing of step S51 and step S53 at a time using the projection matrix as shown in Equation 6. -ing As a result, only the background object 84 is subjected to the enlargement scaling as described above. In step S55, a drawing process for drawing a game image in the designated drawing area, that is, the frame buffer 48 is executed, and the geometry rendering process is returned.

  According to this embodiment, the game image is generated by parallel projection and the background object other than the character object is enlarged and displayed as if viewed from directly above, so that the background object is displayed on a television screen or the like. When the target object is moved along the non-target object, the moving direction of the object by the operation of the controller can be matched with the moving direction of the object on the game screen. That is, the operation is simple.

  Further, since the length of the background object in the depth direction can be accurately expressed by enlarging and scaling, there is no sense of incongruity in operation.

  Furthermore, since the character objects other than the background object are dealt with so as not to be deformed due to enlargement scaling, the reality of the game world is not unnecessarily impaired. Therefore, it is possible to prevent a decrease in interest in the game.

  In the above-described embodiment, the background object is enlarged and scaled in the vertical direction of the monitor screen, but may be reduced in the horizontal direction of the monitor screen. In such a case, the background object can be displayed as seen from directly above by multiplying it by 1 / scale in the horizontal direction.

  In the above-described embodiment, since all objects are enlarged and scaled, the character object is reduced in advance in the horizontal direction in order to prevent the character object from becoming an extended image during drawing. However, normal parallel projection conversion may be performed only on the character object, and enlargement scaling may be performed only on other objects.

  Furthermore, in the above-described embodiment, the game system in which the video game apparatus and the monitor are provided separately has been described. However, the portable game apparatus in which the monitor and the game apparatus are provided integrally, the mobile phone having the game function, Needless to say, the present invention can be applied to a computer such as a PDA or a laptop PC.

It is an illustration figure which shows the game system of one Example of this invention. It is a block diagram which shows the electrical structure of the video game device shown in FIG. FIG. 3 is an illustrative view showing a memory map of a main memory shown in FIG. 2. It is an illustration figure which shows an example of the virtual space where a character object, a background object, and a virtual camera are arrange | positioned, and its game image. It is an illustration figure which shows the state which parallel projected the background object which rearranged virtual space in visual field space. FIG. 10 is an illustrative view showing a state in which a background object and a character object projected in parallel on a screen are written in a drawing buffer. It is an illustration figure which shows an example of the game image at the time of enlarging scaling only to the upper surface of a background object. It is an illustration figure which shows the visual field space which rearranged another example of the virtual space where a character object, a background object, and a virtual camera are arrange | positioned according to the normal camera matrix. Illustrated diagram showing another example of virtual space where character object, background object and virtual camera are arranged, and visual field space where the virtual space is rearranged according to the camera matrix with the calculation method changed so that the sides of all objects are shortened It is. FIG. 10 is an illustrative view showing a state in which the visual field space shown in FIG. 9 is projected in parallel and enlarged scaling is performed, and an illustrative view showing another example of the game image. It is an illustration figure which shows the image of the background object seen from the virtual camera, and the image which performed the scaling scaling while projecting the image in parallel. It is a flowchart which shows the game process of CPU shown in FIG. It is a flowchart which shows the matrix production | generation process of CPU shown in FIG. It is a flowchart which shows the geometry rendering process of GPU shown in FIG. It is an illustration figure which shows an example of the game image displayed with the conventional game device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Game system 12 ... Game device 18 ... Optical disk 22 ... Controller 34 ... Monitor 34a ... Speaker 36 ... CPU
38 ... Memory controller 40 ... Main memory 42 ... GPU
52 ... DSP
54 ... ARAM
62 ... Audio I / F

Claims (14)

Projecting and drawing a state of a three-dimensional virtual space in which a target object that is an operation target of the operation means and a plurality of non-target objects other than the operation target are arranged, onto a projection plane based on a virtual camera in the virtual space and drawing An image generation program for causing a computer to execute a process of generating an image visible from the virtual camera by drawing in an area,
The computer,
For enlarging or reducing the non-target object projected on the projection plane with respect to any one of the first direction on the projection plane of the virtual camera or the second direction orthogonal to the first direction Magnification calculating means for calculating a magnification based on an angle at which the virtual camera is directed with respect to a horizontal plane in the virtual space, and parallel projecting the non-target object to the projection plane and projecting to the projection plane An image generation program for causing a non-target object to be enlarged or reduced based on the magnification and to function as a projection drawing unit that draws the non-target object in the drawing area.   The magnification calculating means projects the projection so that a horizontal cross-sectional shape of the non-target object projected onto the projection plane is substantially the same as a horizontal cross-sectional shape of the non-target object before projection conversion in the virtual space. The image generation program according to claim 1, wherein the computer is caused to function so as to calculate a magnification for enlarging or reducing in a first direction or a second direction on a plane based on an angle at which the virtual camera is facing. . Causing the projection / drawing means to execute enlargement / reduction processing on all objects in a clipping region in the virtual space;
Causing the computer to further function as an arrangement means for reducing or enlarging the horizontal cross-sectional shape of the target object so that the shape of the target object returns to the original shape when the enlargement or reduction process is executed. The image generation program according to claim 1 or 2.   The projection drawing unit generates a determinant for performing the parallel projection conversion and enlarging or reducing based on the magnification, and performing projection conversion and enlarging or reducing processing based on the determinant, and then performing the drawing The image generation program according to claim 1, wherein the computer is caused to function so as to draw the object in a region.   The image generation program according to any one of claims 1 to 4, further causing the computer to function as camera angle detection means for detecting an angle of the virtual camera facing a horizontal plane of the virtual space.   6. The image generation program according to claim 1, wherein the enlargement direction is a vertical direction with respect to the projection plane, and the reduction direction is a transverse direction with respect to the projection plane.   The image generation program according to claim 1, wherein the non-target object includes a terrain object or a building object. Projecting and drawing a state of a three-dimensional virtual space in which a target object that is an operation target of the operation means and a plurality of non-target objects other than the operation target are arranged, onto a projection plane based on a virtual camera in the virtual space and drawing An image generation device that generates an image visible from the virtual camera by drawing in an area,
For enlarging or reducing the non-target object projected on the projection plane with respect to any one of the first direction on the projection plane of the virtual camera or the second direction orthogonal to the first direction Magnification calculating means for calculating a magnification based on an angle at which the virtual camera is directed with respect to a horizontal plane in the virtual space, and parallel projecting the non-target object to the projection plane and projecting to the projection plane An image generation apparatus comprising: a projection drawing unit that enlarges or reduces the non-target object based on the magnification and draws the non-target object in the drawing area.   The magnification calculating unit is configured to cause the projection so that a horizontal cross-sectional shape of the non-target object projected onto the projection plane is substantially the same as a horizontal cross-sectional shape before projection conversion of the non-target object in the virtual space. The image generation apparatus according to claim 8, wherein a magnification for enlarging or reducing in a first direction or a second direction on a plane is calculated based on an angle at which the virtual camera is facing. The projection drawing means executes an enlargement or reduction process on all objects in a clipping region in the virtual space,
Arrangement means for reducing or enlarging the horizontal cross-sectional shape of the target object so that the shape of the target object returns to the original shape when enlargement or reduction processing is executed by the projection drawing means The image generation apparatus of Claim 8 or 9 provided.   The projection drawing means generates a determinant for performing the parallel projection conversion and enlarging or reducing based on the magnification, and after performing projection conversion and enlarging or reducing processing based on the determinant, the drawing The image generation apparatus according to claim 8, wherein the object is drawn in a region.   The image generation apparatus according to claim 8, further comprising camera angle detection means for detecting an angle of the virtual camera facing a horizontal plane of the virtual space.   The image generation apparatus according to claim 8, wherein the enlargement direction is a vertical direction with respect to the projection plane, and the reduction direction is a transverse direction with respect to the projection plane.   The image generation apparatus according to claim 8, wherein the non-target object includes a terrain object or a building object.

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